Heuristic methods for JobShop scheduling

This repository contains the starter code for the assignment.

Compile

Compilation instructions are given for Linux. On windows you can use the gradlew.bat script.

❯ ./gradlew build  # Compiles the project
❯ ./gradlew jar      # Creates a fat-jar in build/libs/JSP.jar

The compiled jar is now build/libs/JSP.jar can be executed like so :

❯ java -jar build/libs/JSP.jar --solver basic --instance ft06

The command line above indicates that we want to solve the instance namedft06 with the basic solver. It should give an output like the following :

                         basic
instance size  best      runtime makespan ecart
ft06     6x6     55            1       60   9.1
AVG      -        -          1.0        -   9.1

Fields in the result view are the following :

• instance: name of the instance
• size: size of the instance {nom-jobs}x{num-tasks}
• best: best known resultfor this instance
• runtime: time taken by the solver in milliseconds (rounded)
• makespan: makespan of the solution
• ecart: normalized distance to the best result: 100 * (makespan - best) / best

One can also specify multiple solvers (below basic and random) and instances (below ft06, ft10 and ft20) for simultaneous testing:

❯ java -jar build/libs/JSP.jar --solver basic random --instance ft06 ft10 ft20

                         basic                         random
instance size  best      runtime makespan ecart        runtime makespan ecart
ft06     6x6     55            1       60   9.1            999       55   0.0
ft10     10x10  930            0     1319  41.8            999     1209  30.0
ft20     20x5  1165            0     1672  43.5            999     1529  31.2
AVG      -        -          0.3        -  31.5          999.0        -  20.4

Here the last line give the average runtime and ecart for each solver.

usage: jsp-solver [-h]  [-t TIMEOUT] --solver SOLVER [SOLVER ...]
                  --instance INSTANCE [INSTANCE ...]

Solves jobshop problems.

named arguments:
  -h, --help             show this help message and exit
  --solver SOLVER [SOLVER ...]
                         Solver(s) to use  (space  separated  if  more than
                         one)
  -t TIMEOUT, --timeout TIMEOUT
                         Solver  timeout  in  seconds   for  each  instance
                         (default: 1)
  --instance INSTANCE [INSTANCE ...]
                         Instance(s) to  solve  (space  separated  if  more
                         than one)

Running directly from Gradle

The project can be executed directly with gradle by specifying the arguments like so :

❯ ./gradlew run --args="--solver basic random --instance aaa1 ft06 ft10 ft20"

This notably ensures that sources have been recompiled whenever necessary.

IDE Support

Most IDEs should provide support for importing gradle projects.

• Eclipse: https://www.vogella.com/tutorials/EclipseGradle/article.html
• IntelliJ: https://www.jetbrains.com/help/idea/gradle.html#gradle_import_project_start